The proposed research is part of a major research effort that seeks to determine the functional consequences of fetal tissue neurotransplantation following spinal cord injury in the cat. The specific project will ascertain the behavioral, electrophysiological, and anatomical effects of fetal spinal cord transplants after a complete transection of the cat sacrocaudal spinal cord. In this unique model of spinal cord injury, only the tail is influenced by sacrocaudal lesions; there are no hindlimb or bladder dysfunctions. In a quantitative behavioral setup, tail segmental reflexes will be measured in normal cats, cats with lesions only, or cats with a lesion and a transplant. In addition, the effects of supraspinal control on tail behaviors, mediated through the transplant, will be determined in plank walking and jumping tasks. In related studies on the same group of animals, the physiological and anatomical effects of the transplants on sacrocaudal neural circuitry will be investigated. The approaches will be applied in concert, to correlate the effects of this spinal cord repair technique. The results will provide valuable new functional information, heretofore unavailable, about the strengths, limitations and potential benefits of fetal spinal cord transplants.